The present invention relates generally to apparatus and methods for treating chronic occlusive pulmonary disease, and more particularly to apparatus and methods for enhancing or assisting breathing, particularly exhalation from one or more regions of a lung using exhalation from a healthier region of the lung.
Patients with chronic bronchitis or other chronic occlusive pulmonary disease (xe2x80x9cCOPDxe2x80x9d) may have reduced lung capacity and/or efficiency due to lung tissue breaking down. For example, in severe chronic pulmonary disease, e.g., emphysema, lung tissue may be damaged or destroyed, reducing the ability of the lung to effectively transfer oxygen. One of the problems with emphysema and like conditions is that the lungs become over-inflated, filling the chest cavity and preventing the patient from being able to inhale effectively.
In severe emphysema cases, lung volume reduction surgery (xe2x80x9cLVRSxe2x80x9d) has been suggested to improve lung efficiency. LVRS is performed by opening the chest cavity, retracting the ribs, and stapling off and removing a diseased or partially diseased portion of a lung. This may allow the remaining healthier lung tissue to inflate more fully within the chest cavity, thereby increasing lung efficiency. LVRS, however, is an extremely invasive procedure, and exposes the patient to substantial postoperative complications.
Accordingly, apparatus and methods for assisting breathing in patients having COPD and like conditions, possibly avoiding the need for open surgery, would be considered useful.
The present invention is directed to apparatus and methods for treating chronic occlusive pulmonary disease, and particularly to lung assist apparatus and to methods for using such apparatus to enhance and/or assist breathing, particularly exhalation from one or more regions of a lung. Preferably, the apparatus and methods of the present invention use air flowing from a healthy region of a lung to assist exhalation of air from a damaged or diseased region of the lung.
In accordance with a first aspect of the present invention, an apparatus is provided that includes a support structure that is implantable within a branch between a main passage and first and second branches. The support structure includes a first end, a second end, and a lateral opening therebetween. The support structure may be expandable between a contracted condition for facilitating insertion into the lung, and an enlarged condition for implantation proximate the branch. For example, the support structure may include a tubular mesh, possibly including engagement elements, such as barbs, for engaging tissue surrounding the branch.
A tubular member, e.g., a nozzle, including an inlet end, an outlet end, and an inner lumen and an outer surface extending therebetween, may be carried by the support structure such that the inlet end is disposed proximate the first end, and the outlet end is disposed proximate the lateral opening. The apparatus preferably defines an outer lumen between the outer surface of the nozzle and the support structure. A first valve may be disposed across the outer lumen for controlling flow through the outer lumen in a predetermined manner. Preferably, the first valve is configured for permitting flow through the outer lumen towards the inlet end and/or for limiting flow through the outer lumen towards the outlet end. More preferably, the first valve is configured to close to prevent substantial air flow through the outer lumen towards the second end of the support structure, and cause air to pass through the inner lumen in order to exit out the second end, thereby generating a vacuum at the lateral opening.
Optionally, the apparatus may include a second valve for limiting flow into or out of the lateral opening of the support structure. Preferably, the second valve is configured to open when a vacuum is generated in the lateral opening to allow air flow into the lateral opening towards the second end of the support structure. More preferably, the second valve is also configured to close when a vacuum is absent from the lateral opening, thereby preventing substantial air flow out of the lateral opening.
The nozzle, first valve, and/or second valve may be substantially permanently attached to the support structure, e.g., by struts. Alternatively, one or more of the components may be attachable to the support structure. In a further alternative, one or more of the components may be implanted independently within a lung proximate a branch, e.g., a bifurcation, such that, optionally, the support structure may even be eliminated.
Preferably, the first end of the support structure in its enlarged condition and the outlet end of the nozzle have a predetermined relative cross-section for generating a predetermined vacuum in the lateral opening when air passes through the inner lumen and out the outlet end. The predetermined vacuum may be selected to induce a desired flow rate into the lateral opening, e.g., from a diseased or damaged region of a lung, as described further below.
In accordance with another aspect of the present invention, a method is provided for assisting air flow through a branch in a lung. Generally, the branch includes a main passage, e.g., a bronchus or bronchiole, a first branch communicating with a healthy region of the lung, and a second branch communicating with a region of the lung to be at least partially isolated. The isolated region may be a diseased or damaged region, e.g., including diseased and/or damaged tissue (although the region may also include at least some healthy tissue).
Initially, a nozzle device may be provided that includes a nozzle or other tubular member including an inlet end, an outlet end, and an inner lumen and an outer surface extending therebetween. The nozzle device may also include a first valve disposed adjacent the outer surface, the first valve being configured to close and/or limit flow along the outer surface from the inlet end towards the outlet end. Preferably, the first valve is configured to open for allowing flow along the outer surface from the outlet end towards the inlet end and to close for restricting or preventing substantial flow along the outer surface from the outlet end to the inlet end, as described above.
The nozzle device may be implanted in the branch such that the inlet end is disposed in the first branch, and the outlet end is disposed proximate the second branch. Preferably, the first valve closes during exhalation to force air from the first branch to pass through the inner lumen into the main passage, thereby inducing a vacuum at the second branch for drawing air from the damaged region into the main passage. During inhalation, the first valve preferably opens to allow substantially unlimited flow into the first branch from the main passage.
A second valve may be implanted in the second branch, the second valve configured to open during exhalation to allow air to be drawn from the isolated region into the main passage, and configured to close during inhalation to prevent air from being drawn into the isolated region.
In one method, a support structure may be implanted within the branch. For example, the support structure may include a tubular mesh that is expandable between a contracted condition for facilitating delivery into a lung, and an enlarged condition for engaging tissue at the branch. After implantation of the support structure, the device may be introduced and secured to the support structure, e.g., by struts extending from one of the nozzle device and the support structure and cooperating slots, detents, or other connectors on the other of the nozzle device and the support structure.
Alternatively, the nozzle device may include a support structure to which the nozzle, first valve, and/or second valve are substantially permanently attached. Thus, the entire nozzle device may implanted in one step, e.g., by securing the support structure to tissue at the branch.
Other objects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings.